A LCD panel comprises an array substrate and a color filter substrate opposite to each other with liquid crystal material interposed therebetween. The LCD panel comprises a display region for displaying and a periphery region outside one side edge of the display region. A plurality of gate lines and a plurality of source lines are vertical to each other and are disposed within the display region of the array substrate, and a thin film transistor array is formed at respective intersections of the gate lines and source lines to drive pixel units for display. Gate leads and source leads are disposed in the periphery region of the array substrate so as to connect the gate and source lines to gate and source driving units, respectively, and black matrix (BM) is disposed in the periphery region of the color filter substrate. In each thin film transistor, a source electrode is connected to the source line, a gate electrode is connected to the gate line, and a drain electrode is connected to a pixel electrode. Liquid crystal molecules are driven to display images by controlling a voltage between the pixel electrode and a common electrode. According to the position of the common electrode, the LCD panel may be divided into vertical electric field LCD panel and horizontal electric field LCD panel.
Vertical electric field LCD panel comprises twisted nematic (TN) LCD panel, vertical alignment (VA) LCD panel, or the like, in which the common electrode is disposed on the color filter substrate, so that an electric field generated by the common electrode and the pixel electrode is vertical to the array substrate.
Horizontal electric field LCD panel comprises in-plane switching (IPS) LCD panel and fringe field switching (FFS, also referred as ADS) LCD panel, in which the common electrode is disposed on the array substrate, so that an electric field generated by the common electrode and the pixel electrode is substantially parallel to the array substrate. In IPS LCD panel, the pixel electrodes and the common electrodes are shaped into stripe and alternatively arranged at intervals. In FFS LCD panel with advanced fringe field switching (AFFS) mode, the common electrode is plate in shape, and a plurality of stripe pixel electrodes are disposed on the common electrode with an insulating layer interposed between the common electrode and the stripe pixel electrodes. In FFS LCD panel with high-aperture ratio of fringe field switching (HFFS) mode, as shown in FIG. 1, the pixel electrode 6 is plate in shape, and a plurality of stripe common electrodes 7 are disposed on the pixel electrode 6 at intervals with an insulating layer 8 therebetween.
As shown in FIG. 1, when the LCD panel is activated, initialization should be performed at first. At this time, the voltage of each of gate leads 42 is changed from 0V into positive value (e.g., 15V), so that a large induced electromagnetic field is generated in periphery region 92. Induced charges are generated on black matrix 22 (i.e., above the gate leads 42) of the periphery region 92 in the color filter substrate 2 due to the induced electromagnetic field, and may disperse into edges of the display region 91. With respect to the horizontal electric field LCD panel, the induced charges may be accumulated at edges of the display region 91 and affect the distribution of electric field, so that undesired rotation of the liquid crystal molecules occurs, and thus white lines are emerged at edges of the display region 91 and the display quality is reduced. When the panel starts displaying normally, the voltage of the gate leads 41 is changed line by line in scanning manner, so the induced electromagnetic field is reduced and the induced charges gradually drop away, and thus the white lines are disappeared.
In order to eliminate the white lines during activating the horizontal electric field LCD panel, there mainly are two ways in prior art. One is to delay in turning on the backlight source, that is, the backlight source is closed when the induced charges are being accumulated, so that users can not see the white lines. The other is to increase the width of the periphery region, and simultaneously increase the distance between the gate leads or the distance between the gate leads and the display region, so that the intensity of the induced electromagnetic field is decreased, or the induced charges is prevented from dispersing into the display region.
The applicant found the following problems in the prior art: with respect to delaying in turning on the backlight source, the activating time becomes longer, which adversely affects user's visual experience and the display quality is reduced; with respect to increasing the width of the periphery region, it must lead to a decrease in utilization of the periphery region, so the size of the LCD panel and the cost are both increased. That is, the existed methods can not essentially solve the problem about the white lines during activating the horizontal electric field LCD panel.